Inlet particle separator systems and methods

ABSTRACT

An inertial inlet particle separator system for a vehicle engine is provided. A separator assembly and collector assembly are coupled to the scavenge flow path and configured to receive the scavenge air. The collector inlet has a throat defining a cumulative throat area at each position along the throat length from the first throat end to the second throat end. The collector body defines a cross-sectional area associated with each position along the throat length between the first throat end and the second throat end. The collector outlet is coupled to the collector body such that scavenge air flows into the collector inlet, through the collector body, and out through the collector outlet. At a first position between the first throat end and the second throat end, the respective cross-sectional area of the collector body is greater than or equal to the respective cumulative throat area.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of application Ser. No.15/092,820, filed Apr. 7, 2016. application Ser. No. 15/092,820 is acontinuation in part of application Ser. No. 13/621,764, filed Sep. 17,2012, and issued as U.S. Pat. No. 9,314,723 on Apr. 19, 2016. Thisapplication claims priority to application Ser. No. 15/092,820 andapplication Ser. No. 13/621,764, which are both hereby incorporated byreference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with Government support under W911W6-08-2-0001awarded by the U.S. Army. The Government has certain rights in thisinvention

TECHNICAL FIELD

The present invention generally relates to fluid inlets for vehicleengines, and more particularly relates to methods and systems forseparating particles flowing into vehicle engines, such as aircraftengines.

BACKGROUND

During operation, fluids such as air are pulled from the atmosphere intoan engine and used to generate energy to propel the vehicle. The fluidsmay contain undesirable particles, such as sand and dust, which maycause issues for engine components. In order to prevent such issues, atleast a portion of the undesirable particles are removed from the fluidsusing an inertial inlet particle separator.

A conventional inertial inlet particle separator typically includes aduct system with a fluid inlet that transitions into 1) a scavengechannel that forms an in-line fluid path with the fluid inlet and 2) aclean channel that branches off from the in-line fluid path. As the namesuggests, inertia tends to cause the particles to travel in a straightline rather than follow the curved fluid flow path. This being the case,particles and a portion of the air carrying the particles tend to flowstraight into the scavenge channel rather than curve into the cleanintake channel. As such, the clean air is separated from thecontaminated air and guided into the engine. The contaminated air isguided from the scavenge channel into a blower or other type of suctionsource and discharged. Approximately 15-25% of the fluid entering thefluid inlet typically enters the scavenge channel, while the remainingfluid and lighter particles enter the clean channel. As designed, thefluid entering the scavenge channel includes most of the largerparticles such that only a small percentage of particles enter theengine through the clean channel, thereby protecting engine components.

Although some conventional inertial inlet particle separators aresuccessful in providing relatively clean fluid to the engine, they mayalso have the adverse impact of increasing the pressure loss of the airentering the engine, with the attendant decrease in engine power outputand increase in fuel consumption.

Accordingly, it is desirable to provide improved methods and systems forseparating particles from inlet fluid for a vehicle engine. Furthermore,other desirable features and characteristics of the present inventionwill become apparent from the subsequent detailed description of theinvention and the appended claims, taken in conjunction with theaccompanying drawings and this background of the invention.

BRIEF SUMMARY

In accordance with an exemplary embodiment, an inertial inlet particleseparator system for a vehicle engine is provided. The system includes aseparator assembly defining a fluid inlet for receiving inlet air, and ascavenge flow path and an engine flow path configured to separate theinlet air into scavenge air and engine air such that the scavenge air isdirected into the scavenge flow path and the engine air is directed intothe engine flow path. The system further includes a collector assemblycoupled to the scavenge flow path and configured to receive the scavengeair. The collector assembly includes a collector inlet coupled to thescavenge flow path. The collector inlet has a throat extending from afirst throat end to a second throat end to define a throat length. Thethroat defines a cumulative throat area at each position along thethroat length from the first throat end to the second throat end. Thecollector assembly further includes a collector body coupled to thecollector inlet along the throat length. The collector body defines across-sectional area associated with each position along the throatlength between the first throat end and the second throat end. Thecollector assembly further includes a collector outlet coupled to thecollector body such that scavenge air flows into the collector inlet,through the collector body, and out through the collector outlet. At afirst position between the first throat end and the second throat end,the respective cross-sectional area of the collector body is greaterthan or equal to the respective cumulative throat area.

In accordance with an exemplary embodiment, an inertial inlet particleseparator system for a vehicle engine includes a separator assemblydefining a fluid inlet for receiving inlet air. The separator assemblyfurther includes a scavenge flow path and an engine flow path andconfigured to separate the inlet air into scavenge air and engine airsuch that the scavenge air is directed into the scavenge flow path andthe engine air is directed into the engine flow path. The system furtherincludes a collector assembly coupled to the scavenge flow path of theseparator assembly. The collector assembly is bifurcated to form a firstcollector assembly portion configured to receive a first portion of thescavenge air and a second collector assembly portion configured toreceive a second portion of the scavenge air.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe following drawing figures, wherein like numerals denote likeelements, and wherein:

FIG. 1 is a block diagram of an inlet particle separator system forsupplying clean air to an engine in accordance with an exemplaryembodiment;

FIG. 2 is a partial, more detailed cross-sectional view of the separatorsystem of FIG. 1 in accordance with an exemplary embodiment;

FIG. 3 is a partial isometric view of the separator system of FIG. 1 inaccordance with an exemplary embodiment;

FIG. 4 is a front view of a collector of the separator system of FIG. 1in accordance with an exemplary embodiment;

FIG. 5 is a partial isometric view of the collector of FIG. 4 inaccordance with an exemplary embodiment; and

FIG. 6 is a chart illustrating collector body cross-sectional area andcumulative throat area, each as a function of circumferential collectorposition;

FIG. 7 is an isometric view of an inlet particle separator system ofFIG. 1 in accordance with another exemplary embodiment;

FIG. 8 is a further isometric view of the inlet particle separatorsystem of FIG. 7 in accordance with an exemplary embodiment; and

FIG. 9 is an isometric view of a collector assembly of the inletparticle separator system of FIG. 7 in accordance with an exemplaryembodiment.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Furthermore, there is no intention to be bound by any theorypresented in the preceding background or the following detaileddescription.

Embodiments described herein provide inertial inlet particle separatorsystems and methods for separating particles from an inlet fluid andproviding the clean fluid to an engine. Particularly, the systems andmethods bifurcate the collector flow paths to reduce the distance thatthe scavenge flow must travel to the outlet. The system and methodsadditionally have a geometric configuration in which a collector bodycross-sectional area is greater than a cumulative collector inlet throatarea. As a result, such systems and methods may reduce pressure loss andincrease separation and operation efficiency.

FIG. 1 is an exemplary block diagram of an inertial inlet particleseparator system 100 coupled to an engine 102. The engine 102 may be,for example, a turbine engine of an aeronautical vehicle such as ahelicopter. The engine 102 receives air from the separator system 100,compresses the air to elevate the air pressure, adds fuel, ignites themixture, and uses the combustion gases to drive a series of turbines,the work from which may be used to propel the vehicle or generateelectricity.

Particularly, and as discussed in further detail below, the separatorsystem 100 receives inlet air 104 and provides relatively clean air 106for use by the engine 102. The separator system 100 includes an inertialinlet particle separator assembly 110 that receives the inlet air 104.The separator assembly 110 separates the inlet air 104 into the engineair 106 provided to the engine 102 and the scavenge air 108. Thescavenge air 108 is drawn into a collector assembly 150 by a fan 152 andthen exhausted into the atmosphere as exhaust air 112. In oneembodiment, the fan 152 may be electric and function to induce thescavenge air 108 into the separator system 100. Although not shown, theseparator system 100 may include sensors, controllers, adjustmentmechanisms and/or other components.

Since the scavenge air 108 must be separated and exhausted, drawingscavenge air 108 in addition to engine air 106 through the inlet resultsin some pressure loss to the engine 102. If unaddressed, excess pressureloss may contribute to degraded performance of the engine 102 and/orrequire increased operation of the fan 152 with the associated energycost. As described in greater detail below, the collector assembly 150may be configured to enable a more efficient operation of the separatorsystem 100, and thus, a more efficient operation of the engine 102.

FIG. 2 is a partial, more detailed cross-sectional view of the separatorsystem 100 of FIG. 1 in accordance with an exemplary embodiment. Inparticular, FIG. 2 illustrates a portion of the separator assembly 110and the collector assembly 150. As described above, inlet air 104 entersthe separator assembly 110 and is separated into scavenge air 108 andengine air 106. Scavenge air 108 with debris and dirt particles flowsinto the collector assembly 150, while relatively clean engine air 106flows from the separator assembly 110 into the engine 102 (FIG. 1), asdescribed in more detail below. As used herein, the term “axial”generally refers to an orientation or direction parallel to the enginecenterline and the term “radial” generally refers to an orientation ordirection perpendicular to the engine centerline. The axial and radialdirections are indicated by legend 200 in FIG. 2.

The separator assembly 110 is defined by a hub 210 and a shroud 220. Theshroud 220 typically circumscribes the hub 210 to define an annular flowpath 230 for the inlet air 104 in an upstream portion of the separatorassembly 110. A splitter 240 is positioned to divide the flow path 230into a scavenge flow path (or channel) 232 and an engine (or clean) flowpath (or channel) 234. As such, the scavenge flow path 232 is defined bythe splitter 240 and the shroud 220, and the engine flow path 234 isdefined by the splitter 240 and the hub 210. As described in greaterdetail below, the scavenge flow path 232 is fluidly coupled to thecollector assembly 150, and the engine flow path 234 is fluidly coupledto the engine 102.

The hub 210 and shroud 220 are configured to separate the inlet air 104,which may include dirt and other debris, into the relatively cleanengine air 106 and scavenge air 108, which carries the debris into thecollector assembly 150. Particularly, the hub 210 includes a radialelement 212 that forces the inlet air 104 from a generally axialorientation into a partially outward radial direction. As the inlet air104 flows radially outward, the debris that forms the scavenge air 108tends to engage the shroud 220 and maintain a flow along the shroud 220into the scavenge flow path 232 as a result of inertia. However, therelatively clean engine air 106 may flow radially inward and radiallyaround the radial element 212, closer to the hub 210, and into theengine flow path 234. As such, the engine air 106 is separated from thescavenge air 108.

As shown in FIG. 2, the scavenge flow path 232 is coupled to an inlet250 of the collector assembly 150. The collector assembly 150 generallyincludes a radial passage 252 extending from the inlet 250 and definedby a vortex fence 254 and a downstream wall 256. The collector assembly150 further includes a collector body 258 extending from the radialpassage 252. In particular, the collector body 258 is coupled to theradial passage 252 at a throat 260, which may be defined at thetermination of the vortex fence 254. The radial passage 252 and thethroat 260 may be considered as part of the inlet 250 or the collectorbody 258. The collector body 258 may be at least partially defined by aportion of the downstream wall 256, an outer circumferential wall 262,an upstream wall 264, an inner circumferential wall 266, and the vortexfence 254. The vortex fence 254 generally prevents flow circulatingthrough the collector body 258 from blocking flow from the throat 260from entering the collector body 258, thereby reducing pressure lossesin the collector assembly 150. As an example, vortex flow 202 isdepicted in FIG. 2 flowing through the collector body 258. Although thevortex flow 202 is generally depicted as a vortex in FIG. 2, asdescribed above, the flow 202 is also flowing circumferentially aroundthe collector assembly 150. In any event, the configuration of the innercircumferential wall 266 and the vortex fence 254 function to maintainthe vortex shape of the flow 202 as the flow 202 flows close to thethroat 260. In other words, the flow 202 is directed along the innercircumferential wall 266 in a generally radial and axial direction, andas the flow 202 meets the vortex fence 254, the flow 202 is directedgenerally radially outward. As a result of this arrangement, the flow202 is directed past the throat 254 instead of flowing towards thedownstream wall 256 and avoid and/or mitigates interference of the flow202 with the flow through throat 260, e.g., by directing flow 202 to alocation adjacent to the throat 260 and/or in the same radially outwarddirection as the flow through the throat 260. As described below, thecollector body 258 may be a scroll or partial scroll to collect anddischarge the scavenge air 108.

FIG. 3 is a partially transparent, isometric view of the separatorsystem 100 of FIGS. 1 and 2. A portion of the air flowing through theseparator system 100 is depicted in the view of FIG. 3. As shown in FIG.3 and introduced above, inlet air 104 flows into the separator assembly110 in which the inlet air 104 is separated into relatively clean engineair 106 and relatively dirty scavenge air 108. The clean engine air 106flows out of the separator assembly 110 into the engine (not shown). Thescavenge air 108 flows into the collector assembly 150. For example, thescavenge air 108 flows into the inlet 250, through the radial passage252, and into the collector body 258.

FIG. 3 particularly shows the annular nature of the separator assembly110. As described above, in one exemplary embodiment, the collector body258 at least partially wraps around separator assembly 110. Thecollector body 258 is coupled to an outlet 270, which is oriented in agenerally axial direction such that the scavenge air 108 flowing throughthe collector body 258 is exhausted out of the collector assembly 150through the outlet 270.

Although FIG. 3 shows a slice of inlet air 104 in a radial-axial plane,the separator assembly 110 generally has an annular inlet such that theinlet air 104 flows into the separator assembly 110. As the inlet air104 is separated, the scavenge air 108 continues to flow into thecollector body 258. In other words, the collector body 258 continues toreceive additional scavenge air 108 along the circumferential length ofthe collector body 258, as discussed in greater detail below.

Additional details about the collector assembly 150 are provided belowwith reference to FIGS. 4 and 5. FIG. 4 is a front (or upstream) sideview of the collector assembly 150 according to an exemplary embodiment.FIG. 4 particularly illustrates the outer circumferential wall 262, theupstream wall 264, and the inner circumferential wall 266. FIG. 4additionally shows the inlet 250 and outlet 270 of the collectorassembly 150. As noted above and additionally referring to FIGS. 2 and3, the scavenge air 108 flows into the inlet 250, through the radialpassage 252, through the collector body 258, and out of the outlet 270.

In one exemplary embodiment, the collector assembly 150 may bebifurcated. In other words, as shown in FIG. 4, the collector assembly150 may include a partition 400. In one exemplary embodiment, thepartition 400 may be a wall positioned within the collector body 258 andgenerally extending in an axial-radial plane to circumferentially dividethe collector body 258 into a first collector body portion 410 and asecond collector body portion 420. The throat 260 defining the entry ofthe body portions 410, 420 may be similarly considered respective firstand second throat portions 460, 470 (e.g., the body portions 410, 420and throat portions 460, 470 respectively form collector assemblyportions). Each of the throat portions 460, 470 may be considered tohave a first throat portion end at the partition 400 and a second throatportion end at the outlet 270 to define respective throat portionlengths. In some embodiments, the partition 400 may additionally extendthrough the radial passage 252 and/or inlet 250 to circumferentiallydivide the entire collector assembly 150. In any event, as shown in FIG.4, the partition 400 is typically arranged at a circumferential positionapproximately 180° from the outlet 270 such that the first and secondcollector body portions 410, 420 have approximately the samecircumferential lengths, e.g., using the outlet 270 as a reference point(labeled 0° in FIG. 4), each of the collector body portions 410, 420 hasa length of approximately 180°.

During operation, if scavenge air 108 enters the collector assembly 150on a circumferential first side of the partition 400, the scavenge air108 flows through the first collector body portion 410 in a firstcircumferential direction, as indicated by arrows 414. If scavenge air108 enters the collector assembly 150 on a circumferential second sideof the partition 400, the scavenge air 108 flows through the secondcollector body portion 420 in a second circumferential direction, asindicated by arrows 424. In the view of FIG. 4, the firstcircumferential direction of air flowing through the first collectorbody portion 410 is clockwise, and the second circumferential directionof air flowing through the second collector body portion 420 iscounter-clockwise. The first and second body portions 410, 420 are eachcoupled to the outlet 270 such that the air flowing through each bodyportion 410, 420 flows out through the common outlet 270, although otherembodiments may have separate outlets.

A conventional collector assembly may have a complete scroll collectorbody. As such, conventional collector assemblies require the scavengeair to travel potentially 360° from an initial circumferential scrollposition to the collector outlet. The relatively long distance mayresult in a pressure drop along the length of the collector scroll body,thereby requiring increased power in the fan to draw scavenge air alongthe length and/or compromised performance with respect to the scavengeair removed from the engine air.

By comparison, the collector assembly 150 in FIG. 4 is bifurcated suchthat the maximum circumferential path that the scavenge air 108 musttravel is only 180° (e.g., from the partition 400 along the firstcircumferential length of the body portion 410 to the outlet 270 or fromthe partition 400 along the second circumferential length of the bodyportion 420 to the outlet 270). Since the bifurcated circumferentialflow path is only half that of conventional collector assemblies, thepressure drop through the collector body 258 is improved. As such,collector assembly 150 may provide an improvement in separationperformance and/or reduction in power to the fan 152. An additional oralternative mechanism to improve performance is discussed below withreference to FIG. 5.

FIG. 5 is a partially transparent schematic, isometric view of thecollector body 258 of the collector assembly 150 of FIGS. 1-4 inaccordance with an exemplary embodiment. FIGS. 1-4 are referenced belowin the description of FIG. 5. As described above, the scavenge air 108flows into the collector body 258 through the throat 260. FIG. 5illustrates a visual representation of a throat area (A_(thr)) and onecollector body cross-sectional area (A_(x-sec)). As described in greaterdetail below, a cumulative throat area (A_(cum) _(_) _(thr)) andcollector body cross-sectional area (A_(x-sec)) may be manipulated toprovide improved performance In one exemplary embodiment, the ratio ofcollector body cross-sectional area (A_(x-sec)) to cumulative throatarea (A_(cum) _(_) _(thr)) is at least one (e.g., A_(x-sec)/A_(cum) _(_)_(thr)≥1). In some embodiments, the ratio of collector bodycross-sectional area (A_(x-sec)) to cumulative throat area (A_(cum) _(_)_(thr)) is generally constant along the length of the collectorassembly. In other embodiment, the ratio of collector bodycross-sectional area (A_(x-sec)) to cumulative throat area (A_(cum) _(_)_(thr)) is varies along the length of the collector assembly.

An example of the relationship between collector body cross-sectionalarea (A_(x-sec)) and cumulative throat area (A_(cum) _(_) _(thr)) isprovided with reference to FIG. 6, which is a chart illustratingexemplary calculations. Reference is additionally made to FIGS. 2 and 5.In the example provided by FIG. 6, the collector body cross-sectionalarea (A_(x-sec)) and cumulative throat area (A_(cum) _(_) _(thr)) areconsidered with respect to 15° increments in which the partition 400 isconsidered 180° and the outlet 270 is considered 0°. In this example,the bifurcated collector body 258 is circumferentially symmetric, e.g.the first body portion 410 has generally identical characteristics tothe second body portion 420, such that only half (or) 180° of thecollector body 258 needs to be illustrated.

FIG. 2 illustrates one exemplary position of a throat width (b_(thr))and throat radius (R_(thr)) to calculate the cumulative throat area(A_(cum) _(_) _(thr)) and the collector body cross-sectional area(A_(x-sec)). As an example, for a 15° segment length, the throat area(A_(thr)) may be expressed as Equation (1), as follows:

A _(thr)=2*π*R _(thr)*15°/360°*b _(thr)   Equation (1)

The collector body cross-sectional area (A_(x-sec)) is a local, radialcross-section represented by the shaded area in FIG. 2 and may becalculated based on the dimensions of the downstream wall 256, outercircumferential wall 262, upstream wall 264, inner circumferential wall266, and the vortex fence 254. In the discussion below, the collectorbody cross-sectional area (A_(x-sec)) is the cross-sectional area at therespective circumferential position. FIG. 5 additionally illustrates anexemplary collector body cross-sectional area (A_(x-sec)) 500 and acorresponding cumulative throat area (A_(cum) _(_) _(thr)) 502. Althoughthe collector body cross-sectional area (A_(x-sec)) generally increasesalong the length of the collector body 258, the area may be limited bypackaging and overall size considerations for the separator system 100.As such, considering that the collector assembly 150 is designed suchthat the collector body cross-sectional area (A_(x-sec)) is greater thanthe cumulative throat area (A_(cum) _(_) _(thr)), the throat width(b_(thr)) must typically decrease along the throat length to maintainthis relationship.

Equation (1) described above generally provides an equation for throatarea (A_(thr)) in a radial passage, such as that shown in FIG. 2.However, in alternate embodiments, the throat and/or collector body maybe axial and/or axial and radial. In general, exemplary embodiments mayrepresent a throat cross-sectional area (A_(thr)) for a 15° segment asexpressed in Equation (2), as follows:

A _(thr)=π*(R _(thr) _(_) _(o) +*R _(thr) _(_) _(i))15°/360°*b _(thr)  Equation (2)

where

R_(thr) _(_) _(o) is the outer radius of the throat, and

R_(thr) _(_) _(i) is the inner radius of the throat.

In one exemplary embodiment, the throat width (b_(thr)) may be linearlyreduced along the length of the throat, e.g., a reduction of about 60%,although any reduction may be provided. However, in other embodiments,the throat width (b_(thr)) may be reduced to any width and/or in anon-linear manner In further embodiments, the throat width (b_(thr)) mayremain constant and/or increase.

FIG. 6 depicts an exemplary plot 650 in which the cross-sectional area(A_(x-sec)) of the collector body 258 and cumulative throat width(A_(cum) _(_) _(thr)) are plotted as a function of circumferentialposition, which additionally illustrates that the cross-sectional area(A_(x-sec)) of the collector body 258 is greater than the cumulativethroat width (A_(cum) _(_) _(thr)) throughout the length of thecollector body 258. It should be noted that this ratio may be maintainedeven if the collector body 258 is not bifurcated, e.g., for lengthsgreater than 180°, including 360°.

FIGS. 2-6 depict embodiments in which the circumferential flow path isbifurcated into two path portions such that the maximum circumferentialpath that the scavenge air must travel is 180°. However, otherembodiments may be provided the divide the circumferential flow pathinto more than two path portions, as will be discussed in greater detailbelow with reference to FIGS. 7-9.

FIG. 7 is an isometric view of an inlet particle separator system 700 inaccordance with another exemplary embodiment. Unless otherwise noted,the system 700 of FIG. 7 may correspond to the system 100 of FIGS. 1-6.As shown in FIG. 7, the system 700 may include a separator assembly 710and a collector assembly 750. Generally, the view in FIG. 7 is anexternal view of the separator assembly 710 and collector assembly 750in an upstream direction. FIG. 7 additionally depicts the FADEC (fullauthority digital engine control) unit 752 that receives the scavengeair from the collector assembly 750.

FIG. 8 is further isometric view of the inlet particle separator system700 of FIG. 7 in accordance with an exemplary embodiment. Relative toFIG. 7, FIG. 8 depicts the system 700 without the FADEC unit 752. FIG. 9is an isometric view of the collector assembly 750 removed from otherportions of the system 700.

The separator system 710 depicted in FIGS. 7 and 8 generally correspondsto the separator assembly 110 depicted in FIGS. 1-3 that receives theinlet air and separates the inlet air into the engine air provided tothe engine and the scavenge air drawn into the collector assembly 750.Also similar to the previous exemplary embodiments, and using FIG. 9 asa reference, the collector assembly 750 may be considered to have anouter circumferential wall 862, an upstream wall 864, and an innercircumferential wall 866. FIG. 9 additionally shows the inlet 850 andoutlet 870 of the collector assembly 750. As noted above (additionallyreferring to FIGS. 2 and 3), the scavenge air 108 flows from theseparator assembly 710 (or 110) into an inlet 250, through a radialpassage 252, through the collector body 858, and out of the outlet 870.Contrary to the collector assembly 150 depicted in FIGS. 2-6, however,the collector assembly 750 of FIGS. 7-9 separates the scavenge air intomore than two path portions.

In particular, and referring to FIG. 9, the collector assembly 750 maybe divided into four path portions. For example, the collector assembly750 may include four partitions 901-904 that divide aspects of thecollector assembly 750 into the respective portions. Each partition901-904 may be a wall, strut, or other separating element positionedwithin the collector assembly 750. As shown, partitions 901-904 functionto divide the collector assembly 750 into first, second, third, andfourth inlet or throat portions 911-914. In some embodiments, thepartitions 901-904 function to divide the collector assembly 750 intofirst, second, third, and fourth collector body portions 921-924.Generally, a “partition” refers to any element that functions toseparate two portions. For example, a closed end on a structure may beconsidered a partition with respect to an adjacent structure. In thedepicted embodiment, each of the throat portions 911-914 and/orcollector body portions 921-924 extend approximately 90° along thecircumference of the collector assembly 750.

The collector assembly 750 in FIGS. 7-9 may also be considered to havean outlet 870 with two outlet portions 931, 932 (or two outlets 931,932). The first outlet portion 931 is positioned in between the firstand second throat portions 911, 912 and in between the first and secondbody portions 921, 922 (e.g., at partition 902). The second outletportion 932 is positioned in between the third and fourth throatportions 913, 914 and in between the third and fourth body portions 923,924 (e.g., at partition 904). During operation, air flowing into thefirst and second throat portions 911, 912 respectively flow through thefirst and second body portions 921, 922 and out through the first outletportion 931. Similarly, air flowing into the third and fourth throatportions 913, 914 respectively flow through the third and fourth bodyportions 923, 924 and out through the second outlet portion 932. Airflowing through the first, second, third, and fourth body portions921-924 are respectively depicted schematically by arrows 941-944. Asshown in FIG. 9, the maximum path traveled by the air within eachportion 921-924 is 90°.

Similar to the embodiments of FIGS. 2-6, the embodiments of FIGS. 7-9are subject to a particular relationship between collector bodycross-sectional area (A_(x-sec)) and cumulative throat area (A_(cum)_(_) _(thr)), Specifically, the ratio of collector body cross-sectionalarea (A_(x-sec)) to cumulative throat area (A_(cum) _(_) _(thr)) is atleast one (e.g., A_(x-sec)/A_(cum) _(_) _(thr)≥1). In some embodiments,the ratio of collector body cross-sectional area (A_(x-sec)) tocumulative throat area (A_(cum) _(_) _(thr)) is generally constant alongthe length of the collector assembly. In other embodiments, the ratio ofcollector body cross-sectional area (A_(x-sec)) to cumulative throatarea (A_(cum) _(_) _(thr)) varies along the length of the collectorassembly.

In one exemplary embodiment, this relationship holds true for each ofthe throat portions 911-914 and collector body portions 921-924,particularly for any position between a partition 901-904 and an outletportion 931, 932, such as any position between a first end at arespective partition 901-904 to a second end at a respective outletportion 931, 932. For example, for any position between partition 901and outlet 931 in the direction of air flow (e.g., from 0° to 90°), thecollector body cross-sectional area (A_(x-sec)) of the body portion 921will be at least as large as the cumulative throat area (A_(cum) _(_)_(thr)) at that position. Moreover, for any position between partition903 and outlet 931 in the direction of air flow (e.g., from 180° to90°), the collector body cross-sectional area (A_(x-sec)) of the bodyportion 922 will be at least as large as the cumulative throat area(A_(cum) _(_) _(thr)) at that position. This relationship is alsoapplicable from 180° to 270° and from 0° to 270°. As described ingreater detail above, this relationship between cumulative throat area(A_(cum) _(_) _(thr)) and collector body cross-sectional area(A_(x-sec)) provides improved performance by improving pressure drop asair flows through the collector body.

Although exemplary embodiments are described above with respect to aninertial inlet particle separator system operating in air and thereforeseparating contaminated air from clean air, the present invention may beapplied to inertial particle separators operating in or utilizing otherfluids. For example, a fluid may be in the form of a liquid rather thanair, as may be used in ships, submarines, and/or other watercraft.

While at least one exemplary embodiment has been presented in theforegoing detailed description of the invention, it should beappreciated that a vast number of variations exist. It should also beappreciated that the exemplary embodiment or exemplary embodiments areonly examples, and are not intended to limit the scope, applicability,or configuration of the invention in any way. Rather, the foregoingdetailed description will provide those skilled in the art with aconvenient road map for implementing an exemplary embodiment of theinvention. It being understood that various changes may be made in thefunction and arrangement of elements described in an exemplaryembodiment without departing from the scope of the invention as setforth in the appended claims.

What is claimed is:
 1. A method for separating particles in an inertialinlet particle separator system, the method comprising the steps of:inducing an inlet fluid into a fluid inlet; separating the fluid intoscavenge air entering a scavenge flow path and engine air entering anengine flow path; bifurcating the scavenge air into a first portion ofthe scavenge air directed into a first collector assembly portion and asecond portion of the scavenge air directed into a second fluidcollector assembly portion, wherein the first collector assembly portionincludes a first throat portion that directs the first portion of thescavenge air into a first collector body portion, the first throatportion and the first collector body portion configured such that eachcross-sectional area of the first collector body portion is greater thanor equal to a corresponding cumulative first throat portion area; andexhausting the first and second portions of the scavenge air through acommon outlet.
 2. The method of claim 1, wherein, at all positionsbetween the first throat end and the first position, the respectivecross-sectional area of the collector body is greater than or equal tothe respective cumulative throat area.
 3. The method of claim 1,wherein, at all positions between the first throat end and the secondthroat end, respective ratios between respective cross-sectional areasof the collector body and respective cumulative throat areas aregenerally constant.
 4. The method of claim 1, wherein, at all positionsbetween the first throat end and the second throat end, the respectivecross-sectional area of the collector body is greater than or equal tothe respective cumulative throat area.
 5. The method of claim 1, whereinthe collector assembly includes a first partition that divides thethroat into a first throat portion and a second throat portion, thecollector body having a first body portion along the first throatportion and a second body portion along the second throat portion. 6.The method of claim 5, wherein the collector outlet includes a firstoutlet portion and a second outlet portion, and wherein the first bodyportion directs a first portion of air to the first outlet portion andthe second body portion directs a second portion of air to the secondoutlet portion.
 7. The method of claim 5, wherein the collector outletincludes a first outlet portion and a second outlet portion, and whereinthe first body portion directs a first portion of air to the firstoutlet portion and the second body portion directs a second portion ofair to the first outlet portion.
 8. The method of claim 5, wherein thecollector assembly is a circumferential collector assembly with acircumference, and wherein each of the first and second throat portionsextends approximately 90° of the circumference.
 9. The method of claim8, wherein the collector assembly further comprises second, third, andfourth partitions that additionally divide the throat into a thirdthroat portion and a fourth throat portion, each separate from the firstand second throat portions, and wherein the collector body furtherincludes a third body portion along the third throat portion and afourth body portion along the fourth throat portion.
 10. The method ofclaim 9, wherein the first throat portion extends between the first andsecond partitions, wherein the second throat portion extends between thesecond and third partitions, wherein the third throat portion extendsbetween the third and fourth partitions, and wherein the fourth throatportion extends between the fourth and first partitions.
 11. The methodof claim 10, wherein the collector outlet includes a first outletportion and a second outlet portion, and wherein the first and secondbody portions direct air into the first outlet portion and the third andfourth body portions direct air into the second outlet portions.
 12. Themethod of claim 11, wherein the first and second outlets are separatedfrom one another along the circumference by approximately 180°.
 13. Themethod of claim 1, wherein the collector assembly is at least partiallya scroll that surrounds the separator assembly.